Tight ball/loose ball

[Dphariss]

I was out shooting the swivel breech day before yesterday. 50 cal Colerain barrels, 48 twist, round bottom grooves.
Its in the adjust the sights phase prior to final metal finish and some scratching of various metal parts.
Having some .480" RBs left over from the smooth rifle tests. I tried them with a thick patch .020"+ and 75 grains of FFFG Swiss.
The report  was a little "flat" shot 2 shots from each barrel. Poor results.  2" groups for the 2 shots from each barrel

With a .490" ball it shot the pictured groups at 50 yards and had a more authoritative report with the same patch and powder. Did damp patch between shots. These are not really what I would call tight but obviously work pretty well.
Now I need to somehow mark the barrels so I can figure which barrel needs which correction. Magic marker I guess. I should have thought of that BEFORE I shot 6 shots

Smaller of the 2 groups is 1" center to center. I think if I had a better aiming point or blackened the front sights it would have eliminated some of the vertical dispersion. Which I believe was shooter induced. But they are only 3 shots from each barrel too but its worth pursuing obviously

This was with the front sight covering the bull with just a slight amount of black showing at 12 oclock. Need to enlarge the rear sight notch a little and then retest.
 But all in all its showing good promise. The previously perceived hard loading was not in evidence.

The 480 ball loads very easily as might be expected but its simply not going to work by the report if nothing else. Suspect significant gas leakage. To be a really fair I should try the 480s again with a better aiming point but do not like the report/gas leakage indications.
Was too windy to find a fired patch....

Dan

[D. Taylor Sapergia]

Shows promise Dan.  I hope to be in the same position some day with my Antes wender.

[Roger Fisher]

'Ain't' it fun       Sighting in after all that enjoyable work is one of my favorite parts of building my own (If she acts right)

I do believe in tight ball and patch loads.  (.454 with .016 spit patching in my well used Getz)

[Canute Rex]

My rifle has a .50 Colerain barrel and it only started tightening up on the paper when I went to .495 ball and a .020 patch. I tried a .498 ball but I had to jackhammer the thing in. The .50 Colerain barrels have .016 deep rifling and .500 land to land, for an ultimate diameter of .532.

.495 + (2 x .020) = .535, so you get a microscopic bit of compression in the grooves, or at least enough diameter within variation to prevent blow-by. With a well lubed patch it loads easily enough.

The thing that really made my rifle work was the previous owner lapping the bore with an oversized ball bolted to the end of a rod and some valve lapping compound. Before that the rifle had been loading rough and cutting patches on a burr. The bore is like a mirror now.

[northmn]

There is loose and there's ball that rattle down the bore.  485 in a 50 is loose a 480 will rattle.  Gnerally I have had the best luck with 495 for sheer accuracy but have used 490 for loading block stuff for hunting.  Kind of wondering about whether I even need loading blocks.  Sometimes we used to use 500 in the old Douglas barrels.  Smaller ball might work with thin leather?

DP

[Dphariss]

There is loose and there's ball that rattle down the bore.  485 in a 50 is loose a 480 will rattle.  Gnerally I have had the best luck with 495 for sheer accuracy but have used 490 for loading block stuff for hunting.  Kind of wondering about whether I even need loading blocks.  Sometimes we used to use 500 in the old Douglas barrels.  Smaller ball might work with thin leather?

DP

But they shot best in the GM 50 smoothbore.
It is likely in a rifle though that the gas escape is damaging the patch.

Dan

[northmn]

Strange isn't it.  Smoothy shooters claim better accuracy with a smaller ball.  Some 20 gauge claiming a 590 or so.  Most rifle shooters claim otherwise.  Some cliams made about the ball slipping the rifling? Maybe the smoothie is a 50 before being cut,  Our rifles really are 52's 57's etc after rifling depending on designation.  As in 30 claiber being really a 308.

DP

[Dphariss]

Strange isn't it.  Smoothy shooters claim better accuracy with a smaller ball.  Some 20 gauge claiming a 590 or so.  Most rifle shooters claim otherwise.  Some cliams made about the ball slipping the rifling? Maybe the smoothie is a 50 before being cut,  Our rifles really are 52's 57's etc after rifling depending on designation.  As in 30 claiber being really a 308.

DP

It is impossible to really seal a deep grooved RB barrel without some wadding and this may not help accuracy. The patch is simply a gasket that controls gas escape.
Shooting a .662 ball in a .670 bore with wide .008 deep grooves with a .020 patch seals pretty well.
The SBs are far easier to seal of course.
Could be the thick patch seals better. I know that .490s and .495s did not shoot as well as a .480 in the GM SB 50.
Poorly wadded/unwadded loads can cause the ball to "vibrate" in the bore rattling against the side walls.
Or so I have been told.

Dan
 

[northmn]

The "standard" formula for accuracy or starting with a load is to use a ball that fits close to the land diameter and work on patches.  The old Numrich barrels shot pretty good but I liked to use a fairly tight ball with thinner patches.  They were shallow grooved and I doubt if they made .008.  Might use a 495 with a 010 patch which was tight in them.  A 490 loaded easier but did not seem as accurate.  Numrich ran a little tighter bored than the Douglas.  Many had better luck with a 495 in the TC factory barrels with their comprimise rifling than the factory recommended 490.  Some rest type shooter actually use a mallet to tap start a ball that makes slight contact with the lands (this is using a false muzzle).
I sometimes wonder if the real deep groove rifling of over 010 may not be getting to be too much of a good thing. 

DP

[Daryl]

I don't like the deep grooves -- square, any way.  Taylor's Rice barrel is very easy loading with the deep rifling and is clean shooting as well.  He's using a .495" ball and thicker than .020 patches - .023" I think.

My barrels have square rifling with .010" to .012" grooves and all prefer .005"/Under balls.  Even the Enfield with it's .003" rifling at the muzzle loads fairly easily with a .015" and .575".  I believe it's the low pressure that keeps the patches from burning due to it's deep grooves at the breech.  It's .574" bore also shoots well with a .562" ball, but I have to use at least a .0215" patch.

As to the smooth bore with smaller balls shooting better, vs better shooting with larger balls in the rifles - the really aren't that small, simply due to the smoothbore .50 acting as if it's actually a .48cal. rifle with one huge .010" groove as to ball size.  It would probably shoot just fine with a .470" or .475" ball as well. 

[northmn]

I guess this could wander of track, but in a way rifling depth is related to how tight you can load a ball patch combination.  The Numrich barrels were accurate enough for offhand but were not as well rifled as a DouglassXX.  It seemed like you shot them a while or shot them in and then had to change loads to get them to shoot as well which is why I would increase ball size and use a thinner patch.  The Douglas barrels shot about as well as one could ask with the 010 rifling.  Usually even with a 015 patch or 020 patch.  I guess I question the ability to seal a bore as well with cloth when the patch thickness has to be very thick just to fill the grooves.  Its almost like forcing the use of an undersized ball, round groove, square groove or whatever.

DP

[Daryl]

I guess I question the ability to seal a bore as well with cloth when the patch thickness has to be very thick just to fill the grooves.  Its almost like forcing the use of an undersized ball, round groove, square groove or whatever.

DP

I agree - much, however, depends on the pressure involved.  The smaller the bore, the tighter must be the combination.  Larger bores can get by with thinner patching and less compression. 

If compressed hard  enough, even a piece of beer-box cardboard makes a gasget in an engine.